Traditional method of controlling a virtual actor on a computer involves calculating all frames that are to be displayed in advance and storing it inside a movie production application such as a Flash (registered trade mark) movie. With this method all of discrete frames are stored in a memory or a hard disk drive, in a similar manner as film or VTR.
However, with this method, for example, 20 to 30 frames are necessary to create 1 second of movie, and the image quality suffers during video encoding process when storing the video as a movie. As the size of image frame increases, this difference in quality becomes more noticeable. Also, when a virtual actor is able to talk, all mouth movements must be recorded in advance; therefore, when a virtual actor is to enunciate a new word, a problem arises that a new image sequence must be captured again.
On the one hand, in recent years real time morphing technology has advanced and not all frames in between key frames must be prepared in advance in order to smoothly transition from one image to another.
However, using real time morphing technology presumes that a PC is equipped with a graphic accelerator or a vast amount of memory, and hence this is not a realistic option since PCs used by most people are not equipped with graphic accelerators. Also, in order to create complex and natural appearing motion by a virtual actor with real time morphing, the only method available is to write a computer program, which is a very inefficient process method for designing motion since it requires assets such as programming proficiency or proficiency with programs such as a movie creation application; therefore, a problem arises that much of the demand cannot be fulfilled.
Also, traditionally, it was cumbersome to set hotspots, which are trigger points, to control the motion of a virtual actor. For example, in order to set a virtual actor so that rubbing his head makes him happy, the hotspot on the head must move with the head if it moves in the image. Further, there arise problems of how to make independent motions of each body part seem natural, as well as how to use less data to make complex expressions such as tilting the head while smiling, angry, etc. These issues are not restricted to virtual actors on computers, as they relate to general robotic controls.
The above noted conventional technologies are disclosed, for example, by Japanese Unexamined Patent Application Publication No. 2005-135046 and Japanese Unexamined Patent Application Publication No. 2003-204537, which are incorporated herein by reference.